Can you run the i2c_scanner ?http://playground.arduino.cc/Main/I2cScannerIf it doesn't find an I2C addres, you have a display that can not pull the SDA low for an acknowledge. I don't know if the u8glib can do that. I have seen a library for that, perhaps I can try to find it if you want.

Can you run the i2c_scanner ?http://playground.arduino.cc/Main/I2cScannerIf it doesn't find an I2C addres, you have a display that can not pull the SDA low for an acknowledge. I don't know if the u8glib can do that. I have seen a library for that, perhaps I can try to find it if you want.

In that case, you might have a super cheap OLED, that can only read I2C and can not acknowledge it.Does it say 'heltec.cn' on the backside ?

The rar file on this page contains code for it.http://www.wide.hk/products.php?product=I2C-0.96%22-OLED-display-module-%28-compatible-Arduino-%29That code doesn't do anything special, so perhaps the u8glib will work with it.They say it is Adafruit compatible, perhaps you can use the Adafruit library or the u8glib with Adafruit mode.

For the u8glib, you have to ask in the u8glib thread if the display is supported.I only started recently using u8glib with another super cheap OLED.http://forum.arduino.cc/index.php?topic=217290.0

The rar file on this page contains code for it.http://www.wide.hk/products.php?product=I2C-0.96%22-OLED-display-module-%28-compatible-Arduino-%29That code doesn't do anything special, so perhaps the u8glib will work with it.They say it is Adafruit compatible, perhaps you can use the Adafruit library or the u8glib with Adafruit mode.

For the u8glib, you have to ask in the u8glib thread if the display is supported.I only started recently using u8glib with another super cheap OLED.http://forum.arduino.cc/index.php?topic=217290.0